/Engine/Source/Runtime/Engine/Public/ExternalTexture.h
UnregisterExternalTexture
void RegisterExternalTexture ( const [FGuid](API\Runtime\Core\Misc\FGuid) & InGuid, FTextureRHIRef & InTextureRHI, FSamplerStateRHIRef & InSamplerStateRHI, const [FLinearColor](API\Runtime\Core\Math\FLinearColor) & InCoordinateScaleRotation, const [FLinearColor](API\Runtime\Core\Math\FLinearColor) & InCoordinateOffset )